The information contained on this page is provided as general health information and is not intended to substitute as medical advice and direction from your physician or health care provider. Please direct any questions related to your health care provider. In an emergency, call 9-1-1 or go to the nearest emergency center.

Disorders of the parathyroid glands (hormone made by these glands controls calcium and vitamin D levels in the blood)

Disorders that affect how your intestines absorb nutrients

Overactive thyroid gland or taking too much thyroid hormone medicine

Abnormal vitamin D level

Your doctor may also order this test if you have been on bed rest for a long time.

Normal Results

Normal values range from 8.5 to 10.2 mg/dL (2.13 to 2.55 millimol/L).

Normal value ranges may vary slightly among different laboratories. Some laboratories use different measurements or may test different specimens. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

A higher than normal level may be due to a number of health conditions. Common causes include:

Being on bed rest for a long time.

Consuming too much calcium or vitamin D.

Hyperparathyroidism (parathyroid glands make too much of their hormone; often associated with a low vitamin D level).

Infections that cause granulomas such as tuberculosis and certain fungal and mycobacterial infections.

Risks

There is very little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include: